Electric switches



Sept. 25, 1962 L. J. FIGHTER ELECTRIC SWITCHES Filed March 10, 1959 W. Mw

IN V EN TOR.

United States Patent ()fi 3,056,001 Patented Sept. 25, 1962 ice3,056,001 ELECTRIC SWITCHES Ludwig J. Fichter, Chicago, Ill., assignorto Oak Manufacturing Co., a corporation of Delaware Filed Mar. 10, 1959,Ser. No. 798,492 3 Claims. (Cl. 209-67) This invention relates toelectric switches and more particularly to switch constructionsutilizing small permanent magnets for effecting snap action.

In order that the invention may be fully understood, it will bedisclosed in connection with the drawings Wherein FIGURE {1 is aperspective view illustrating one embodiment of the invention.

FIGURES 2 to 5 inclusive are elevations of modifications of structuresembodying the invention.

FIGURE 4a is a perspective of a permanent magnet used in theconstructions illustrated in FIGURES 4 and 5.

Referring first to FIGURE -1, support is provided upon which the variousparts of the switch may be disposed. Support 10 is preferably ofnon-magnetic material and preferably of insulating material and may beof a suitable plastic moulded piece, either in one part or in aplurality of parts cemented or bolted together. Support 10 has endportion 11 in which are rigidly secured fixed contact arms 12 and 13.Contact arms 12 and 13 are of good electrically conducting metal andextend inwardly through portion 11 to interior 15 of the support.Contact arms 12 and 13 carry at their ends small permanent magnets 16and 17. Permanent magnets 16 and 17 may be provided with pole pieces ifdesired. The magnet pole faces function as stationary contacts andcooperate with magnetizable reed part 21. Reed part or armature 21 maybe of spring steel or other ferro-magnetic material such as soft ironwith body 22 of the reed being of spring material. So long as the reedend is ferro-magnetic, it makes little difference whether body 22 of thereed is ferro-magnetic or not. Reed body 22 has portion 23 moulded insupport part 25.

Support 10 has portion 27 extending between ends 11 and 25 of thesupport. Support portion 27 is provided with a suitable opening in whichthere is disposed push button 28. Push button 28 has enlarged head 29terminating in rounded end 30 which is adapted to bear against bodyportion 22 of the reed. The push button has shoulders 32 which limit theoutward movement thereof in support portion 27. Reed 22 is normallybiased as by being sprung so that ferro-magnetic end portion 21 bearsagainst magnet 16 functioning as the top contact. From this position,push button 28 may be moved downwardly to move the reed so that armatureportion 21 will engage the bottom contact portion.

In order to limit the downward movement of push button 28, support 10has bottom portion 34 extending between end portions 11 and 25. Bottomportion 34 has massive anvil portion 35 to limit the downward movementof the push button and reed.

By controlling the relative lever arms of the reed cooperating with thepush button and with the stationary contacts, various sensitivitycharacteristics may be obtained.

Referring now to FIGURE 2, a modification is illustrated wherein portion21' of the reed carries permanent magnet 40. In this modification,stationary contact arms 12 and 13' have end portions 41 and 42 offerro-magnetic material. It is understood that in the constructionsillustrated in FIGURES l and 2, that the pole faces of the permanentmagnets will be at the top and bottom of each magnet. Thus, in FIGURE 1,the pole faces for magnet 16 will be at the top and bottom. In the formillustrated in FIGURE 2., the pole faces for magnet 40 will be the topand bottom faces.

In both modifications, the permanent magnets may be riveted or solderedor secured in any desired fashion to the respective supports. It is notnecessary that arms 12 and 13 in FIGURE 1 or arms 12' and 13 in FIGURE 2be of ferro-magnetic material. It is only necessary in FIGURE 2 thatends 41 and 42 of the contact arms be of ferro-magnetic material.

Referring now to FIGURE 3, an additional modification is shown whereinpermanent magnets 50 and 5-1 are secured in the top and bottom portions52 and 53 of the supporting structure. Magnets 50 and 51 are disposed onopposite sides of reed 55 carrying ferro-magnetic button 56. It isunderstood that ferro-magnetic button 56 ex tends on both sides of thereed so that suitable cooperation with the pole faces of magnets 50 and51 may be effected.

In the modification of FIGURE 3, the magnets do not carry current.Instead, reed 55 has free end 58 carrying movable contact buttons 59 onopposite sides thereof for cooperation with stationary contacts 60 and61 carried by contact support arms 62 and 63. In other respects, themodification of FIGURE 3 is similar to FIGURES 1 and 2 in that the reedneed not be ferro-magnetic but does carry current.

In all cases, the reed is moulded or anchored in the support and isnormally biased upwardly from which position it may be pushed downwardlyby a push button. These three modifications are similar in that the pushbutton acts directly on the reed. It is possible, however, to have thepush button act on a separate reed arm and transmit the reed deflectingforce to the main body of the reed.

Referring now to FIGURE 4 and FIGURE 4a, there is illustrated a modifiedconstruction wherein stationary contact arms 62' and 63' extend onopposite sides of end portion 58' of reed 55'. Reed 55' has portion 65rigidly secured within the end portion of the support structure. Reed55' carries ferro-magnetic armature 56' which is adapted to operatebetween pole faces 68 and 69 of U- shaped permanent magnet 70.Preferably, recesses 71 and 72 are provided in the magnet material atthe inside corners to prevent short-circuiting the magnet.

Magnet 70 is suitably anchored in support 74 and is so disposed thatferro-magnetic pole piece 56' may move between pole faces 68 and 69. Itwill be noted that the distance between pole faces 68 and 69 is somewhatlarger than the width or thickness of armature 56' so that the armaturemay move downwardly from the position shown in FIGURE 4. In the positionillustrated in FIGURE 4, armature 56' is up against pole face 68. In thedownward position of the reed, armature 56' will be clear of pole face68 and will bear against pole face 69.

Reed 55', like the other reeds, is biased to a normal position, hereillustrated as up. It is adapted to be moved downwardly from its upposition by means of push button 76- cooperating with leaf 77 punchedout from the main body of reed 55. It is understood that leaf 77 isstiff enough so that push button 76 when moved downwardly will force thereed down. In this position, armature 56' will go against pole face 69of the permanent magnet and contact portion 58' will cooperate with thebottom contact arm.

Leaf 77 may be punched out from the interior portion of the reed in themanner illustrated, for example, in Patent No. 2,140,792, grantedDecember 20, 1938, or the leaf may be a separate reed portion rigidlyattached to the body portion of the reed. As with the modificationsillustrated in FIGURES l to 3 inclusive, the reed in this form need onlybe electrically conducting and need not be magnetic.

' 3 Referring now to FIGURE 5, a modification of the structureillustrated in FIGURE 4 is shown. In this modification, armature portion156 and movable contact portion 158 have their positions on the reedchanged. In FIGURE 5, the armature portion 156 is at the free end of thereed rather than in an intermediate part of the reed as in FIGURE 4.Similarly, movable contact portion 158 is at an intermediate portion ofthe reed rather than at the end as in FIGURE 4. Auxiliary reed 177extends from the portion on the reed at armature 156 as in FIGURE 4. Itis clear that in both FIGURES 4 and 5, the switch operating forceexerted by push buttons 76 and 176 must be applied to the armature. Asin FIGURE 4, the reed in FIGURE 5 is biased upwardly from which positionit may be moved against this bias by downward movement of push button176.

Due to the fact that permanent magnet 170 in FIGURE 5 cooperates withthe free end of the reed, it is possible to turn the permanent magnet sothat the end of the reed extends toward the bottom or bight of the U. InFIG- URE 4, the bight of the U is laterally offset from the reed.

What is claimed is:

1. An electrical switch comprising an elongated electrical insulating,non-magnetic block, said block as viewed from the side having the shapeof a frame with long top and bottom frame members spaced from each otherand maintained by spaced side members to provide an interior regionaccessible from the side, a pair of fixed contact supporting memberscarried by one frame side member, said fixed contact supporting membersextending through the insulating support to the interior region thereof,the fixed contact supporting portions within the interior region havingfixed contacts at the ends facing each other in opposed spaced relation,a flexible reed supported by the other frame side member and having thebody portion thereof extending toward the first named frame side member,said reed carrying movable contacts on opposite sides thereof, thecontacts forming cooperating contact pairs, at least one of saidcontacts comprising a permanent magnet with the remaining contacts beingof ferro-magnetic material, said reed being normally biased to closeagainst one of the fixed contacts, the contacts having facing planarsurfaces for intimate physical contact with each other throughout thearea of said surfaces, the cooperating magnet action maintaining saidcontacts tight with a maximum magnetic force, a push button mounted inone of the long frame members adjacent the remaining side memher, saidpush button being movable transversely of the reed and having a portionengaging the reed near said other side member, said push button beingmovable to force said reed away from its normal biased position so thatthe reed contact engages the other fixed contact and an anvil portioncarried by the remaining long frame member and disposed opposite thepush button with the reed lying between the two for limiting themovement of said push button whereby said reed is protected from damagedue to excessive pressure upon said push button.

2. The construction according to claim 1 wherein said reed carries apermanent magnet, and the fixed contacts comprise armatures of magneticmaterial.

3. The construction according to claim 1 wherein said fixed contacts arepermanent magnets, and the reed carries an armature of magneticmaterial.

References Cited in the file of this patent UNITED STATES PATENTS2,480,127 Frerer Aug. 30, 1949 2,518,480 Lilja Aug. 15, 1950 2,529,652Dicke Nov. 14, 1950 2,665,344 Zozulin Jan. 5, 1954 2,688,063 GomersallAug. 31, 1954 2,782,278 Peters Feb. 19, 1957 FOREIGN PATENTS 98,871Austria Dec. 27, 1924 163,579 Australia June 24, 1955

